Halaman

Kamis, 31 Mei 2012

Most evenings, if daylight permits, I head out back for thirty minutes of natural solitude. While mowers may hum in the distance or trucks may rumble on a nearby road, I try to focus on the sights, sounds and fragrance through which I stroll. I also try to ignore problems that may have occupied my day or that await my attention tomorrow.

This natural form of stress reduction has become a vital part of my life and, though I make no attempt to search for any particular plants or animals, I generally encounter something unexpected or see it in a different light. More than anything else, these breaks from human responsibilities make me appreciate the calm patience that typifies the lives of wild creatures and, on most evenings, I seem to absorb some of that serenity.

I could be getting some bills paid or subjecting myself to the endless parade of reality shows on cable TV but those thirty minutes are a cherished part of my day. While these outdoor rambles often provide fodder for future blogs, I seek only the company of our wild neighbors and a chance to enter their world, however brief that visit might be.

Rabu, 30 Mei 2012

After enduring two tragic earthquakes within a span of nine days, residents of northeastern Italy are both distraught and mystified. As emphasized in news reports, that region had not experienced a significant earthquake for hundreds of years. Yet, this industrial valley stretches between the Apennines and the Alps, mountain ranges that owe their very existence to the collision of the African and Eurasian Plates.

This tectonic collision, though too gradual to witness during our brief life span, has been going on for at least 40 million years, producing the varied landscape of southern Europe. A quiescent period of seismic activity in any given area, even lasting hundreds or thousands of years, is to be expected as pressure along the collision zone shifts from one region to another. While we may understand the geologic cause for the earthquakes, our inability to accurately predict the timing of such events has become all too clear over the past few decades; nevertheless, scientists in Italy are facing manslaughter charges for their failure to predict the 2009 quake in the Apennines, east of Rome, which killed more than 300 citizens.

We humans have a tendency to blame others for the misfortunes that we endure, even when they arise from the uncontrollable and, to date, unpredictable natural forces that mold our planet. We also tend to interpret our Universe, distant galaxies or local geography, from the narrow perspective of our human life span. Anyone who resides along the active plate margins of Planet Earth cannot afford to ignore the realities of its past and ongoing geologic evolution, however remote the risk of catastrophe might seem at the present time. After all, the Africa-Eurasian collision has been underway for 40 million years, 400 times longer than our own species has walked the planet.

Senin, 28 Mei 2012

Mention Arctic land mammals and the image of large, well-insulated creatures comes to mind: polar bears, musk ox, caribou and the extinct woolly mammoth, to name a few. But the small Arctic fox, the most northern-living canine on our planet, has managed to thrive on the harsh, treeless tundra of the Arctic biome. Equipped with a compact body habitus, thick, dense fur, furred paws and changing coloration to blend with its environment, this hardy fox also has an exquisite sense of hearing for prey location, adapts well to an omniverous diet and produces large litters to sustain its population.

After breeding in late winter or early spring, the monogamous pair uses a large den network in which to raise its litter of 6 to 15 or more kits; the newborn fox will remain with their mother through the summer and, as with some other wild canines, a few yearlings often stay behind to assist with feeding and protecting their younger siblings. The diet of the Arctic fox is dominated by lemmings and other small mammals (including seal pups) but also includes berries, vegetation, carrion, birds, fish and the eggs of seabirds and waterfowl. When food is abundant, they will bury eggs or meat in the Arctic permafrost for consumption during the harsh months of winter.

Circumpolar in their distribution, the populations of Arctic fox are stable in most areas though they are endangered in Scandinavia due to overhunting. Having evolved late in the Pleistocene, about 250,000 years ago, they spread across northern oceans on the vast ice shelves of that Period and are the only mammal native to Iceland. Today, like many polar species, Arctic fox are threatened by global warming that is changing their habitat, altering their food supply and allowing dominant predators (such as red fox and gray wolves) to invade their territory.

Minggu, 27 Mei 2012

It seems very likely that religious beliefs first arose in early human clans (some 130,000 years ago) when gods were invoked to counter fear and suffering. After all, our distant ancestors were traumatized by natural catastrophes, brutal weather, predators, mysterious diseases, fatal injuries, famine and tribal warfare on a regular, if not daily, basis.

At some point during our evolution, certainly by three to four thousand years ago, suffering had become more than the impetus for religious ritual; it had become ingrained in the rites themselves. We humans had come to imagine that our gods are appeased by suffering; as a result, human sacrifice, self-inflicted pain and self denial became an essential part of religious ceremony. Even today, despite our advanced scientific knowledge, such attitudes persist, represented by a wide range of beliefs and rituals, from giving up desserts during Lent to volunteering as a suicide bomber. Orders of monks and nuns retreat to lives of fasting and prayer, Catholic priests take vows of celibacy, devout believers lash themselves with reeds or whips and many (if not most) of the faithful view their earthly suffering as a ticket to heavenly rewards.

Of course, if this delusional, suffering-based faith only affected those who practice it, the rest of us would be free to focus on the enlightenment of human culture. Unfortunately, their beliefs permeate human society, stifling education, fomenting warfare, fostering intolerance and instilling fear in younger generations. Worse yet, those who view suffering as a means to salvation are more willing to inflict its scourge on the innocent. One hopes that we will eventually evolve beyond these primitive delusions but our zealous, god-fearing brethren, obsessed with their image of a vindictive deity, are not likely to fade from the scene anytime soon.

Sabtu, 26 Mei 2012

On this Memorial Day weekend, July has made an early appearance in the Heartland. With afternoon highs in the 90s (F) and overnight lows in the 70s, it feels like mid summer; were it not for the plentiful moisture still in the soil, the vegetation would be wilting in the intense heat, but, in this case, the verdant face of May persists.

This early heat wave is courtesy of a high pressure ridge over the southeastern U.S.; beneath this dome, air is sinking and heating up, retarding cloud formation, while, along its outer edge, thunderstorms will ignite across the Upper Midwest. One crop of storms, off the coast of South Carolina, has developed into Tropical Storm Beryl, which will move WSW along the rim of the dome over the next 24 hours, bringing heavy, much-needed rain to southern Georgia and northern Florida.

The high pressure ridge should stay in place through the holiday weekend and will then drift to the east, allowing cooler and drier air to filter in from the northwest. Until then, we'll endure heat and humidity more typical of July and the Southeastern Coast will receive an early taste of the hurricane season (which officially begins on June 1). Here's hoping that a premature summer ushers in an early autumn!

Jumat, 25 Mei 2012

Having once inhabited most of the United States, mountains lions were extirpated from eastern and central portions of our country by the early 20th Century; an exception was the Florida panther, which managed to survive in the dense vegetation of the Everglades and adjacent cypress swamps. Throughout most of the 1900s, the easternmost populations of cougars (other than the Florida panther) were in West Texas and in the Black Hills of western South Dakota.

However, over the past decade, sightings of mountains lions have increased signficantly across the American Midwest. Almost all of the confirmed cases have been males, presumably banished from their home range by other dominant males; indeed, cougars are territorial and field studies have revealed that the home range of adult males is in the neighborhood of 100-300 square miles. While 5 mountain lions inhabited the Pine Ridge Escarpment of western Nebraska in 2004, 30 were documented by 2011, including females and cubs. Sightings in Kansas, Missouri, Iowa, Minnesota and Wisconsin have involved male cougars that are thought to have wandered eastward from South Dakota and western Nebraska (though some may have arrived from Colorado via the Arkansas River corridor). One famous case involved a male that wandered through Minnesota and Wisconsin in 2009-2010 and ended up getting killed in Connecticut in 2011. Here in Missouri, there have been at least 29 cougar sightings since 1994, though, in some cases, multiple sightings of the same cat may have occurred. Since mountain lions are secretive and primarily nocturnal, an accurate estimate of Midwest wanderers is very difficult to obtain and it is likely that more pass through this region than some human residents might care to imagine; on the other hand, livestock loss to cougars has been minimal since these travelers seem to favor small mammals and the occasional deer.

Of course, unless females begin to follow the nomadic males from mountainous areas of the West, breeding populations will not become established in the Heartland. The increasingly common sightings in recent decades surely reflects the growth of human populations throughout the Mountain West, depriving these predators of their natural habitat and forcing males to head east, following river channels across the Great Plains. Any excitement associated with the opportunity to observe these magnificent cats in the Midwest is tempered by the knowledge that we have driven them from their modern homeland and that they are returning to an ancient homeland that has forever changed. Whether they will be welcomed or persecuted remains to be seen.

Kamis, 24 Mei 2012

Over the past month, loud vreeeps have echoed through our neighborhood on my morning walks to work. Their source is always difficult to locate but these clear, ascending calls seem to arise from the treetops, where the vocalists remain hidden amidst the dense foliage of late spring.

In fact, they are the distinctive calls of great crested flycatchers, colorful insectivores that prefer to hunt in the upper canopy of open, deciduous woodlands; suburbs of the central and eastern U.S. thus appeal to these summer residents. Nesting in tree cavities, great crested flycatchers utilize a wide variety of nesting materials, including human trash and discarded snakeskins; it is only during the collection of these items that they are likely to be seen on the ground and, even then, they fly from site to site, not hopping or walking like most songbirds. The great majority of their time is spent in the trees, snaring insects from leaves and stems or catching them in mid air.

By late summer, great crested flycatchers begin to migrate toward their wintering grounds in the Caribbean, Central America and northern South America. There they feast on insects in the canopy of rain forests and, unlike most migrant songbirds, remain vocal throughout the year.

Rabu, 23 Mei 2012

Amateur naturalists are often confused by the distribution of fossils across our globe, wondering why certain fossils (of dinosaurs, for example) are plentiful in some areas but absent in others. In general, the fossils of plants and animals result from their remains having been trapped within sediment (lake deposits, ocean floor sediment, river mud, volcanic debris, etc.) that, over millions of years, hardened into sandstone, mudstone, limestone or some other sedimentary rock. Of course, most animals and plants die under circumstances in which their remains are consumed, undergo decay or are scattered by predators and natural forces before such fossilization can occur.

The type of fossils present in any region of our planet depends upon the age of the exposed sedimentary rocks in that area; rocks that formed from sediments that accumulated during any given geologic era will harbor fossils of life from that era. The exposure of these sedimentary rocks is a product of regional uplift, erosion and the deposition of overlying sediments (not necessarily occuring in that order). For example, Jurassic sedimentary rock, which accumulated during the Age of Dinosaurs, may have been lifted to the surface (as in large parts of the American West), may be buried deep beneath younger sediments or may have long-since eroded from the surface due to action of streams or glaciers; in other areas, these sediments may have never accumulated in the first place due to regional topography throughout the Jurassic Period.

Millions of years from now, Holocene sedimentary rocks will be explored by our super-human decendants or, perhaps, by visitors from other solar systems. Encased in those rocks will be the fossils of human civilization, including our domestic livestock, our cultivated plants, our pet poodles and the plants and animals that comprise our natural ecosystems. These Holocene sediments may be found deep in canyons, atop mountain ranges or outcropping from desert plains; in many areas they will lie deep beneath the fossilized remnants of younger civilizations while, in others, they will have already washed away to the sea.

Senin, 21 Mei 2012

Those of us who frequently travel across the Great Plains or the Glaciated Plain of the Upper Midwest are usually glad to encounter river valleys, which break the monotony of the flat terrain. In these areas, the primary channel and its tributaries have carved a mosaic of hills, ridges and valleys from the plain, necessitating dips and curves in the route of our journey.

Beyond the topographic relief, these river valleys harbor rich, moist soil, supporting a wide variety of vegetation, offering a sharp contrast from the cropfields, grasslands and sparse woodlands of the adjacent plains. Visually appealing to human travelers, these corridors also attract regional wildlife that utilize them to nest, roost, feed or to escape the harsh conditions on the plain. Indeed, naturalists know that wildlife viewing is significantly more productive along these ribbons of life than it is on the flat terrain that surrounds them; even open-country species tend to congregate near river valleys, a vital source of water and cover.

Of course, river corridors also appeal to those of us who take an interest in regional topography, providing insight into the evolution of Earth's landscape. Unless one is a robotic traveler, oblivious to the environment through which they move, rivers, like mountain ranges and lakes, give us a sense of place and direction, a natural perspective by which to gauge our progress.

Minggu, 20 Mei 2012

As a consequence of the lowest water levels that I have ever encountered at Eagle Bluffs Conservation Area, dead carp lined the central channel, providing a feast for numerous turkey vultures. Usually seen soaring above the countryside, these large scavengers had gathered on the mudflats and levees to partake in the bounty of rotting fish.

Of course, the low water was also beneficial to great blue herons, great egrets and green-backed herons, concentrating their prey in the shallow pools. Other highlights included a large number of wood ducks, the attentive females ushering their broods across the calm waters, and an unusual abundance of migrant shorebirds for late May. Cormorants and diving ducks were noticeably absent but small groups of coot, blue-winged teal and mallards plied the shallows or huddled on the shorelines. Throughout the evening, a steady background chorus was provided by bullfrogs, green frogs, cricket frogs, killdeer and indigo buntings as white-tailed deer emerged from the woods to browse the marshlands and crop fields.

Since the Missouri River is still fairly high, I suspect that the low water at Eagle Bluffs reflects an artificial drawdown, often utilized to mimic natural fluctuations that foster the welfare of native floodplain vegetation while discouraging the invasion of alien species. Whatever the cause, the drought-like conditions surely favor the hunters and scavengers; for the time being, it's vulture heaven at Eagle Bluffs.

Sabtu, 19 Mei 2012

During our travels along the spectacular coast of Lake Superior this week, we encountered a pair of Canada geese, ushering their brood across the unusually calm waters of the lake. West of the roadway was a pristine wetland, stretching out from the mouth of a rushing river; we naturally assumed that the pair had nested within that scenic marsh. Such encounters often make human envious of wildlife, recognizing both their freedom and their capacity to live in beautiful natural landscapes, unencumbered by the responsibilities of the human lifestyle.

On the following day, I saw another pair of geese with their young offspring, resting along a muddy pond in the industrial port of Superior, Wisconsin. Close to a wealth of pristine habitat, far more appealing to the human eye, they had chosen to nest along this unattractive pool, bordered by a litter-strewn lawn. Perhaps, once the goslings fledge, they will move on to a more pristine location but, for now, they appeared to be perfectly comfortable at their ugly urban site.

Unlike most humans, wild creatures focus primarily on their basic needs, not on the physical beauty of their surroundings. While they are far better equipped to wander off to spectacular landscapes that we can only hope to visit, they do not share our obsession with picturesque settings. Of course, neither do they worry about the effects that pollution might have on the welfare of their family; in that respect, they unknowingly depend on the wisdom and commitment of their human neighbors.

Jumat, 18 Mei 2012

Just north of downtown Duluth, Interstate 35 ends and becomes Minnesota Route 61 that hugs the northwest coast of Lake Superior, all the way to the Canadian border. Providing spectacular and ever-changing views of the lake, this road also yields access to a chain of State Parks, most of which surround rivers that rise in the hill country to the west and rumble down to Lake Superior.

A few of these Parks deserve special mention. Gooseberry River State Park, a few miles north of Two Harbors, is accessed by an excellent network of trails that lead past a series of beautiful waterfalls, lead out to cliff-top views of the lake and river valley or take the visitor down to the rocky shore. Temperance River State Park, just north of Taconic Harbor, provides spectacular evidence of the erosive force of moving water; this turbulent stream has cut a deep, rugged gorge through the Precambrian volcanic bedrock, producing waterfalls, whirlpools and polished rock formations. Just shy of the Canadian border, Grand Portage State Park, stretching along the Pigeon River, provides access to Pigeon River Falls, the highest waterfall in Minnesota (120 feet). Finally, a scenic rest-stop, a few miles north of the town of Grand Portage, offers an awe-inspiring view of Lake Superior, its coastal hills, the offshore Susie Islands and the distant silhouette of Isle Royale, stretching across the northeastern horizon.

While towns, marinas, resorts and industrial ports are also spaced along Superior's Northwest Coast, they do not begin to detract from its fabulous natural landscape and the abundance of State Parks, State Forests and dedicated Wilderness could keep any naturalist entertained for months, if not years. Our only regret is that we had too little time to explore that scenic wonderland.

Selasa, 15 Mei 2012

Facing an off-week and yearning to get back to the North Country after our memorable journey across the Upper Peninsula of Michigan, last September, my wife and I decided to head for western Lake Superior. We left Columbia yesterday afternoon, driving north across the Glaciated Plain of northern Missouri and eastern Iowa, stopping for the night in Iowa City. This morning, we resumed our journey, dropping into the Mississippi Valley at Marquette, Iowa, and then paralleling the broad river and its wooded islands along the Wisconsin (eastern) shore. Scenic bluffs rise along both sides of the Mississippi Valley in this "Driftless Area" of the Upper Midwest, which was spared the erosive force of Pleistocene Glaciers.

Protected within the Upper Mississippi National Wildlife Refuge, access to the Mississippi and its varied riparian habitats is rather limited (except for boaters). However, Goose Island County Park, just south of La Crosse, Wisconsin, provided an excellent opportunity to study the floodplain wetlands, backwater bays and eastern channel of the river; birding was excellent at the Park. North of La Crosse, we cut away from the Mississippi for a more direct route to Duluth, Minnesota, where we are spending the night on that city's restored waterfront.

In the coming days, we plan to explore the northwest coast of Lake Superior and the Apostle Islands region of northern Wisconsin. So far, wildlife encounters have been limited to bald eagles, sandhill cranes, common loons, gulls, aquatic turtles and a host of waterfowl and songbird species. But we are now in wolf and moose country and I look forward to the possibility of seeing (or hearing) those North Country residents amidst the spectacular landscape that adjoins America's grandest Lake.

Jumat, 11 Mei 2012

Ever since early man discovered natural herbs and resins that seemed to ease his common maladies, we humans have been hooked on drugs. In the modern world, these heavily marketed agents are used to counteract the effects of our sedentary lifestyle or to rescue us from poor choices when it comes to our diet and recreational activities.

Of course, some pharmaceutical products have had a major impact on the health and longevity of the human species: vaccines, antibiotics and chemotherapeutic agents for some cancers (especially childhood leukemias) come immediately to mind. But many of our prescription drugs would not be necessary if we engaged in a healthy lifestyle and they often impose new health problems related to their side effects. Statins, the classic miracle drugs of the past decade or so, have been touted as the ultimate answer to preventing cardiovascular disease and are heavily advertised on American television; yet, within the past few months, evidence has surfaced that associates higher doses of some statins with an increased risk of developing diabetes. And just this week, studies were released that question the long term use of bisphosphonates, drugs used to combat osteoporosis; also heavily marketed on TV, these agents prevent reabsorption of bone, a natural process in the regular remodeling of our skeleton. The new studies reveal that, despite their remarkable effects in the first few years, these agents may be associated with long term effects that could actually increase the risk of future fractures.

These ongoing revelations regarding the long term effects of unnatural chemical agents are hardly a surprise to those of us in the medical profession. We regularly encounter patients who are taking twenty or more drugs, prescribed to combat maladies that are often secondary to inactivity, obesity, tobacco use or the excessive consumption of alcohol. The prevention of disease, including cardiovascular disease and osteoporosis, is best addressed through regular exercise, a healthy, balanced diet and the choice to forgo smoking and other self-inflicted risks. While the use of some medications may become necessary, there is no such thing as a miracle drug.

Rabu, 09 Mei 2012

Looking at a map of Earth, one sees a complex of mountain ranges from Southeast Asia to Spain. Almost all of these ranges are relatively young, having crumpled skyward throughout the Tertiary Period; in fact, all are still rising today, a fact made evident by frequent earthquakes across this swath of landscape.

About 55 million years ago (MYA), soon after the Rocky Mountains formed in North America, the Indian Subcontinent began to collide with southern Asia, forcing up the Himalayas and its associated ranges, from southern China to Afghanistan. By 40 MYA, the Red Sea and Gulf of Aden began to open, splitting the Arabian Plate from Africa and pushing it northward into southwestern Asia; this compressed the crust of that region, lifting the ranges of Iran, eastern Turkey and the Middle East. About the same time, as the Tethys Sea was closing, Africa drifted northward to collide with southern Europe; this has crumpled up the Alps and its associated ranges, from western Turkey and Greece to the Pyrenees of Spain. In concert, regional subduction of the African Plate beneath the Eurasian Plate has produced a chain of volcanos along the western edge of Italy.

In some areas, such as the Pyrenees, older mountain ranges, having eroded to low hills, were renewed by these Tertiary orogenies. Today, as these tectonic forces persist and the "new" mountains continue to rise, the agents of erosion combat their uplift; molded by glaciers and incised by streams, their rock dust is carried off to the sea where, millions of years in the future, it may resurface as the core of another mountain range.

Selasa, 08 Mei 2012

Rising at the west end of Great Slave Lake in Canada's Northwest Territories, the Mackenzie River flows northwestward for almost 1100 miles to the Beaufort Sea. Un-dammed and winding through Subarctic and Arctic wilderness, its wide, braided channel is just the final conduit of a massive watershed that covers 20% of Canada, extending from northeast British Columbia, northern Alberta, northwest Saskatchewan and the western Yukon to the massive Mackenzie River Delta, the 12th largest on our planet. If one includes its most distant tributaries, this river system exceeds 2600 miles in length (the longest in Canada) and drains a watershed of almost 700,000 square miles.

To the southwest, the Peace and Athabaska Rivers rise on the east side of the Continental Divide in the northern Canadian Rockies; these large streams merge to form a large inland delta along Lake Athabaska, which drains to Great Slave Lake via the Slave River. Leaving Great Slave Lake, the Mackenzie River picks up meltwaters from the Mackenzie Mountains (to its west) via the Liard River system and then receives flow from Great Bear Lake, to its east, the largest lake in Canada. At its braided delta, just east of the Richardson Mountains, the Mackenzie discharges copious amounts of relatively warm, fresh, nutrient-rich water into the Arctic Ocean; this annual discharge, the 14th largest on Earth, dramatically affects the regional ecosystem, allowing boreal woodlands to extend well north of their usual range and increasing the diversity of plants and animals across the ever-changing delta. Beluga whales gather here in spring to molt in the mild river current and the countless, shallow lakes provide ideal breeding habitat for shorebirds, tundra swans and snow geese. Resident mammals include black bears, barren ground grizzlies, Arctic fox, Arctic wolves, caribou, moose, musk ox and a massive number of muskrats.

However, all is not well in this seemingly pristine wilderness. Dams on tributaries of the Mackenzie have reduced flow through its primary channel and are diminishing the annual floods that are crucial to the welfare of its delta ecosystem. In addition, worrisome levels of mercury have been found in the river over the past few years, the product of mining and power plant effluent across the watershed. Of course, as with other Arctic ecosystems, global warming may dramatically affect the natural diversity of this magnificent yet fragile landscape.

Senin, 07 Mei 2012

After wilting in central Missouri over the last two days, enveloped in tropical heat and humidity, I arrived along the Colorado Front Range late this afternoon under low clouds and scattered showers; the temperature was 45 degrees F. These two weather extremes were produced by the same Pacific storm system; ahead of the front, muggy air was pumped into the Midwest from the Gulf of Mexico while, behind it, a plume of moisture was swept westward through the cool air. Since this flow is counterclockwise around the storm's central low, the moisture arrived from the northeast, the classic upslope direction for Metro Denver. Cooling and condensing as it rose across the western landscape, the plume dumped its cargo of moisture across northeastern Colorado.

Over the past 24 hours, Metro Denver received a half inch of rain in most areas while higher elevations to the west and south collected .75 inch or more, a welcome respite from the recent drought. Checking the foothills as I arrived from the east, it was obvious that the upslope shroud was beginning to lift though jet traffic was still landing to the north and likely offering a bumpy descent through the showers and virga. Our Littleton farm clearly benefited from the moisture, having taken on the untidy overgrowth that promises plenty of yard work this week.

As the system continues to move eastward, the muggy air and thunderstorms will be confined to the Eastern Seaboard and high pressure will reclaim the Heartland, bestowing warmth and sunshine for the days ahead. Here along the Front Range, the wind will shift to the south-southwest, a downsloping direction for Metro Denver; we expect sunshine, mild temperatures and a chance to dry out.

Sabtu, 05 Mei 2012

Hot, humid air has been flowing into Missouri for the past two days and will continue for at least another 24 hours. This muggy, southern soup is courtesy of both a broad high pressure ridge over the eastern half of the U.S. and a slowly approaching Pacific front that should ignite thunderstorms by tomorrow afternoon.

Riding this river of subtropical air, the first wave of common nighthawks appeared in our skies yesterday evening. Among the last migrants of spring, they are more cautious than swallows and swifts, waiting until plenty of insects are reliably available for their late-day feasts. They'll be with us until late summer and, perhaps, as late as early October, departing for the tropics before autumn's chill annihilates their prey.

Meanwhile, here in the Midwest, this summer-like heat in early May is not welcomed by those of us who prefer cool weather. Fortunately, a milder and drier air mass is expected to move in by early next week, bringing spring conditions back to the Heartland. By then, I'll be heading to our Colorado farm, guaranteed to escape the heat and humidity that common nighthawks relish.

Jumat, 04 Mei 2012

What little television I used to watch was primarily devoted to science and nature, with a bit of news and sports on the side. Unfortunately, what remains of that genre is now filled with human melodrama and a mix of reality shows focused on dysfunctional people. If you hope to get a forecast from the Weather Channel, expect to wade through a chorus of zany meteorologists, lifestyle advice experts, tornado chasers, and an ever-expanding collection of programs on characters such as turbine cowboys, bombastic ice pilots and, starting this week, macho iron workers.

The Discovery and History Channels are no better, offering a steady diet of shows on gator hunters, daredevil loggers, bleary-eyed truckers, death-defying crabbers and, just this year, full-metal jousters. Even the storied Nature program on PBS has shifted toward a more humanistic view of the natural world, seemingly in response to the public's drift from true science to emotionally satisfying entertainment. Fortunately, programs such as Frontline and NOVA continue to offer informative and fascinating presentations.

The dearth of good science programming on television is likely a concious effort of media moguls to compete with the varied enticements of the Internet. Grabbing viewers with serious, thoughtful content has, sadly, been largely abandoned. Promising an inside look at the lives of New Jersey Housewives has become their mode of operation and the future of educational television looks bleak indeed.

Kamis, 03 Mei 2012

Based on television images beamed to the world over the past few decades, Afghanistan appears to be a desolate region of rock and sand, a landscape of drought and human carnage. Yet, Afghanistan hosts a spectacular diversity of wildlife and many of its species have been threatened by the recurrent and protracted wars that have ravaged this country.

Among these threatened species are the reclusive snow leopard, markhors (large wild goats), Marco Polo sheep, urials (another wild sheep) and Asiatic black bears. Other native mammals include ibex, gray wolves, leopard cats, caracals, Pallas's cat, stone martens, lynx, Eurasian otters and Kashmir cave bats. At least 500 species of birds have been observed in Afghanistan, 200 of which breed in the country. Raptors include lammergeiers (large vultures), amur falcons, Eurasian eagle-owls and nine species of eagles, including Pallas's fish eagle. Other birds of note include grey herons, Dalmatian pelicans, black storks, greater and lesser flamingos, Himalayan snowcocks,, Demoiselle cranes, great bustards, pheasant-tailed jacanas and whiskered terns. Afghanistan hosts 3 species of bee-eaters, 7 species of sandgrouse, 8 species of shrike, 5 species of wagtail and 3 species of parakeet.

Indeed, when it comes to birds, Afghanistan rivals the Lower 48 of the U.S. in its diversity of species, though migrant and wintering birds account for the majority of its population. But when we consider the wide range of habitat on our Continent compared with the landlocked deserts and mountainous terrain of Afghanistan, its diversity of birds is truly impressive, reflecting the fact that Afghanistan, long a crossroads for human trade and migration, remains an important crossroads for avian travel.

Rabu, 02 Mei 2012

For the past decade, Afghanistan has evoked images of war, political corruption and civil strife. It seems appropriate to shift gears and focus on the natural landscape of that isolated but starkly beautiful region of our planet.

Consulting a map, one finds that the country of Afghanistan is pear-shaped, aligned northeast to southwest; the narrower part, complete with a thin stem of territory that pokes eastward to China, is to the northeast while its broader portion is to the southwest, abutting Iran, western Pakistan and southern Turkmenistan. The high spine of the Hindu Kush, the westernmost extension of the Himalayas, bisects the northeastern half of the country, curving from its northeastern frontier to the heart of Afghanistan; some peaks in easternmost Afghanistan soar above 25,000 feet while elevations gradually decrease toward the west. On either side of this natural divide, numerous streams have carved a maze of ridges, canyons and valleys from the Hindu Kush massif, giving rise to four major river systems.

The Kabul River drains the southeast edge of the Hindu Kush, flowing through the capitol city before cutting through the Spin Ghar Range along the border with Pakistan, where it joins the Indus River. The Helmand River and its tributaries drain the southwestern and western flanks of the Hindu Kush, crossing the southwest plateau region of Afghanistan and eventually flowing westward into Iran. The Hari Rud, rising along the northwest side of the massif, also flows westward into Iran while the Amu Darya, fed by mountain glaciers of the Hindu Kush, snakes westward across the fertile plain of northern Afghanistan, forming its border with Tajikistan, Uzbekistan and Turkmenistan (east to west) before angling northwestward into the latter country. With the exception of the Kabul River, which reaches the sea via Pakistan's massive Indus River system, the rivers of Afghanistan, heavily utilized for irrigation in this dry landscape, eventually disappear into the desert sands of Iran and Turkmenistan.

Selasa, 01 Mei 2012

I will never forget my first encounter with a painted bunting. George, my good friend and fellow birder, was visiting us in Wilmington, North Carolina, in June, 1977. As we headed down to Cape Fear for a morning of birding, George spotted a male painted bunting in roadside shrubbery and nearly rolled his aging Valiant in an effort to stop. Since then, I saw these colorful birds on a regular basis during my years in Arkansas and have more recently encountered them in the glade country of southwest Missouri; indeed, painted buntings favor woodland clearings with scattered shrubs and thickets.

Painted buntings occur in two separate breeding populations; one summers along the Coastal Plain from the Carolinas to northern Florida while the second inhabits the south-central U.S., from southeast Kansas and southwest Missouri through Oklahoma, Arkansas, Louisiana and Texas. The male, easily the most striking bird in the U.S., is identified by his blue head, red abdomen and patches of green and yellow on his back and sides; the female, while less varied, is also colorful, with a bright olive back and yellow-green chest and abdomen. Highly territorial during the breeding season, the male defends his area from a perch and may breed with two females; fights between males are unusually aggressive for songbirds and may end in death. The deep, cup-shaped nest is placed in low vegetation and 1-5 eggs are laid; unfortunately, painted bunting nests are often parasitized by cowbirds, adding to the pressure of habitat loss in the Southeast. A diet of insects and spiders is consumed during the breeding season, fortified with seeds during migrations and on their wintering grounds.

While the Southeastern painted buntings winter in South Florida and the Caribbean, those that breed in the south-central U.S. winter in southern Mexico and Central America. This latter population, like waterfowl but unlike most songbirds, uses migration staging areas (in southern Arizona and northern Mexico) where they molt before continuing on to their wintering sites. As mentioned above, painted buntings are threatened by cowbird parasitism and by habitat loss (especially in the Southeastern U.S.); their colorful plumage is also a liability and a significant number are captured on their wintering grounds for sale in the caged-bird market.